Material transporting conveyors are known, and have been used extensively to provide a way of efficiently transporting granular material from one location to another. Such conveyors are particularly well suited for transporting material such as grain.
Generally, such conveyors have a drive motor, which causes a material transporting member to move the material along. Typically, the material transporting member is in the form of an endless loop, running between a drive sprocket at one end, driven by the drive motor and an idler sprocket at the other end. The material transporting member may have scraper blades, to push the material along. Material is introduced near or at one end, and exits from the conveyor near or at the other end.
With such conveyors, problems can arise because there inevitably will be occasions where the material transporting member becomes jammed, for example because of a misaligned scraper blade, or, the member may break, due to wear, fatigue or the like. In the case of a covered or enclosed conveyor, if the member breaks and the drive motor continues, it will cause the member to accumulate in a heap on the upstream side of drive sprocket. The member may get tangled around the drive sprocket and even further broken. Subsequently, it can be very tedious and difficult to re-thread the member through an enclosed conveyor, which is still half full of material to be transported. In the case of a jam, it is desirable to stop the motor to prevent the member from breaking. For all these reasons, it is desirable to be able to sense if the member has broken or is jammed and, upon such conditions, to be able to stop the drive motor to prevent compounding the problem.